Manufacturing method of electrode

Abstract

To provide a manufacturing method of an electrode capable of efficiently manufacturing a plurality of electrodes.SOLUTION: A manufacturing method of an electrode includes: a first step of preparing a composite sheet having a current collector and an electrode composite layer disposed on at least one surface of the current collector, and having long sides and short sides; a second step of crosslinking the short sides using a first resin sheet; a third step of crosslinking the long sides of the composite sheets adjacent to each other in an extending direction of the long sides using a second resin sheet; a fourth step of disposing a separator on the electrode composite layer in the crosslinked composite sheet; and a fifth step of cutting the crosslinked composite material sheet for each electrode composite material layer to form a single sheet. In the third step, a second resin sheet A supplied from a first roll and a second resin sheet B supplied from a second roll after the second resin sheet A are used to crosslink the long sides, and the second resin sheet A and the second resin sheet B are welded and connected while being pressurized by an impulse heater.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing an electrode. [Background technology]

[0002] Information-related devices and communication devices such as personal computers, video cameras, and mobile phones are becoming widespread. Furthermore, from the perspective of reducing the burden on the environment, electric vehicles and other motor-driven vehicles are becoming more common. Accordingly, various studies are being conducted on the batteries used as power sources for these devices.

[0003] For example, Patent Document 1 discloses that in an energy storage device including an electrode stack formed by stacking a plurality of bipolar electrodes and a sealing body that seals the side surfaces of the electrode stack extending in the stacking direction of the bipolar electrodes, the sealing body has a plurality of frame-shaped sealing members welded to each edge of the current collector and a plurality of frame-shaped spacers arranged between the sealing members adjacent to each other in the stacking direction. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2023-152023 Summary of the Invention [Problem to be solved by the invention]

[0005] It is desirable to efficiently manufacture electrodes. The present disclosure has been made in view of the above circumstances, and a main object of the present disclosure is to provide a method for efficiently manufacturing electrodes. [Means for solving the problem]

[0006] [1] A first step of preparing a plurality of composite sheets each having a current collector and an electrode composite layer disposed on at least one surface of the current collector, and each having long sides and short sides in a planar shape; A second step of cross-linking the short sides of the composite sheets adjacent to each other in the extending direction of the long sides using a first resin sheet; a third step of cross-linking the long sides of the composite sheets adjacent to each other in the extending direction of the long sides using a second resin sheet; a fourth step of disposing a separator on the electrode mixture layer of the crosslinked mixture sheet; a fifth step of cutting the crosslinked composite sheet into individual electrode composite layers, In the third step, the long sides are crosslinked using a second resin sheet A supplied from a first roll and a second resin sheet B supplied from a second roll after the second resin sheet A, and The method for manufacturing an electrode includes welding and connecting the second resin sheet A and the second resin sheet B while applying pressure with an impulse heater. [Effects of the Invention]

[0007] The present disclosure provides an advantage in that a plurality of electrodes can be efficiently manufactured. [Brief explanation of the drawings]

[0008] [Figure 1] 1A to 1C are schematic diagrams illustrating a method for manufacturing an electrode in the present disclosure. [Figure 2] FIG. 10 is a diagram illustrating a third step in the present disclosure. [Figure 3] FIG. 1 is a diagram illustrating a problem to be solved by the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] The electrode manufacturing method according to the present disclosure will be described in detail below with reference to the drawings. The drawings are schematic diagrams, and the size and shape of each part are appropriately exaggerated for ease of understanding.

[0010] FIG. 1 is a schematic diagram illustrating a method for manufacturing an electrode according to the present disclosure. Specifically, FIGS. 1(a) and 1(b) illustrate a first step, FIG. 1(c) illustrates a second step, FIG. 1(d) illustrates a third step, and FIGS. 1(e) and 1(f) illustrate a fourth and fifth steps. FIG. 1(b) is a schematic cross-sectional view of FIG. 1(a), and FIG. 1(f) is a schematic cross-sectional view of an electrode obtained by cutting (slicing) along the dotted line in FIG. 1(e). FIG. 2 is a diagram illustrating the third step according to the present disclosure. In the method for manufacturing an electrode according to the present disclosure, first, a plurality of composite sheets 10 are prepared (first step), each of which includes a current collector 1 and an electrode composite layer 2 (2A, 2B) disposed on at least one surface (p, q) of the current collector 1. The composite sheets 10 have a long side L and a short side S in plan view, as shown in FIGS. 1(a) and 1(b). Next, for adjacent composite sheets 10 in the extending direction of the long sides L, the short sides S are cross-linked using a first resin sheet 20S (second step). Next, for adjacent composite sheets 10 in the extending direction of the long sides L, the long sides L are cross-linked using a second resin sheet 20L (third step). Next, as shown in FIG. 1(e), a separator 30 is placed on the electrode mixture layer 2 of the cross-linked composite sheet 10 (fourth step). Then, as shown in FIGS. 1(e) and 1(f), the cross-linked composite sheet 10 is cut into individual electrode mixture layers 2 to form sheets (fifth step). This results in an electrode 100 as shown in FIG. 1(f). In particular, in the electrode manufacturing method of the present disclosure, as shown in FIG. 2, in the third step, the second resin sheet A (20LA) supplied from the first roll R1 and the second resin sheet B (20LB) supplied from the second roll R2 after the second resin sheet A (20LA) are used to crosslink the long sides (not shown), and the second resin sheet A (20LA) and the second resin sheet B (20LB) are welded and connected while applying pressure with an impulse heater H.

[0011] According to the present disclosure, the second resin sheet A and the second resin sheet B are connected by welding while being pressurized by an impulse heater, so that a plurality of electrodes can be efficiently manufactured.

[0012] In electrode manufacturing processes, to ensure continuous production without interruption, a process known as auto-splicing is used to automatically splice a previously supplied sheet with a later-supplied sheet when the remaining sheet is low. Conventionally, as shown in Figure 3(a), a previously supplied resin sheet 20A and a later-supplied resin sheet 20B are connected using an adhesive material such as adhesive tape. However, as shown in Figure 3(b), this can result in the connection being thicker due to the adhesive material. Furthermore, the connection also requires the thickness of two sheets (resin sheets 20A and 20B). This can lead to unevenness at the connection. In this case, if the connection is included in the finished electrode, a separate deburring process is required. For example, as shown in Figure 1(f), the resin sheet functions as a resin member covering the outer edge of the current collector 1. Therefore, unevenness in the resin sheet can prevent adequate sealing of the electrolyte when used in a liquid-phase battery. Furthermore, when producing multiple electrodes by performing each process (each processing) continuously using roll-to-roll transport, steps at the connection parts may cause meandering, which may result in a deterioration in processing position accuracy.

[0013] In contrast, in the electrode manufacturing method of the present disclosure, the second resin sheet A and the second resin sheet B are connected by welding while being pressurized by an impulse heater, eliminating the need for an adhesive material. Furthermore, the thickness of the connection portion can be reduced by applying pressure. This reduces the occurrence of steps. As a result, the need for the above-mentioned burr removal can be reduced, and meandering can be suppressed, allowing for efficient electrode manufacturing.

[0014] 1.First step The first step is to prepare a plurality of composite sheets each having a current collector and an electrode composite layer disposed on at least one surface of the current collector, and each having long and short sides in a planar shape.

[0015] The current collector may be a member that functions as a positive electrode current collector, a member that functions as a negative electrode current collector, or a member that functions as both. In other words, the composite sheet may be a positive electrode member, a negative electrode member, or a bipolar member. Examples of materials for the current collector include metals such as aluminum, copper, SUS, and nickel. Examples of the shape of the current collector include foil and mesh.

[0016] The electrode mixture layer is a layer disposed on at least one surface of the current collector, and is usually a layer that functions as an active material layer in an electrode. The electrode mixture layer may function as a positive electrode active material layer in an electrode. In other words, the electrode mixture layer may be a positive electrode mixture layer. On the other hand, the electrode mixture layer may function as a negative electrode active material layer in an electrode. In other words, the electrode mixture layer may be a negative electrode mixture layer. Here, as shown in FIG. 1(b), the electrode mixture layer 2 (2A, 2B) is a layer that is formed in a thickness direction D T In this case, it is preferable that one of electrode mixture layers 2A and 2B is a positive electrode mixture layer (positive electrode active material layer) and the other is a negative electrode mixture layer (negative electrode active material layer). On the other hand, mixture layer 2 may be disposed on only one surface of current collector 1.

[0017] The electrode mixture layer contains at least an active material, and may contain at least one of a conductive aid and a binder, as necessary.

[0018] When the electrode mixture layer is a positive electrode mixture layer, the active material (positive electrode active material) may be, for example, an oxide active material. 1 / 3 Co 1 / 3 Mn 1 / 3 Examples of the active material include rock salt layer type active materials such as O2, spinel type active materials such as LiMn2O4, and olivine type active materials such as LiFePO4. Sulfur (S) may also be used as the positive electrode active material.

[0019] When the electrode mixture layer is a negative electrode mixture layer, examples of the active material (negative electrode active material) include Li-based active materials such as metallic lithium and lithium alloys; carbon-based active materials such as graphite, hard carbon, and soft carbon; oxide-based active materials such as lithium titanate; and Si-based active materials such as simple Si, Si alloys, and Si oxides.

[0020] The conductive additive and binder may be materials conventionally known in the field of batteries. The thickness of the electrode mixture layer is, for example, 0.1 μm or more and 1000 μm or less.

[0021] 2.Second process The second step is a step of cross-linking the short sides of composite sheets adjacent to each other in the direction in which the long sides extend, using the first resin sheet.

[0022] In the second step, it is preferable to place a first resin sheet on a first surface in the thickness direction of the current collector and on a second surface opposite to the first surface, to cover the region of the current collector including the short side (short side region).

[0023] The material of the first resin sheet is typically a thermoplastic resin, such as a fluorine-based resin such as polytetrafluoroethylene (PTFE), or an olefin-based resin such as polyethylene (PE) or polypropylene.

[0024] 3. 3rd process The third step is a step of crosslinking the long sides of composite sheets adjacent to each other in the direction in which the long sides extend using a second resin sheet. In particular, in the third step, the long sides are crosslinked using a second resin sheet A supplied from a first roll and a second resin sheet B supplied from a second roll after the second resin sheet A, and the second resin sheet A and the second resin sheet B are welded and connected while being pressurized by an impulse heater.

[0025] The second resin sheet may be made of the same thermoplastic resin as the first resin sheet.

[0026] The details of the third step will be described with reference to FIG. 2. As shown in FIGS. 2(a) to 2(c), in the third step, first, the long sides of the second resin sheet A (20LA) supplied from the first roll R1 are crosslinked. The crosslinking is preferably performed while applying pressure with the pressure roll R3. Then, when only a small amount of the second resin sheet A (20LA) remains, the second resin sheet B (20LB) is supplied from the second roll R2, and the second resin sheet A (20LA) and the second resin sheet B (20LB) are welded and connected while applying pressure with the impulse heater H. The crosslinking then continues with the connected second resin sheet B (20LB). As shown in FIGS. 2(b) and 2(c), the second resin sheet A (20LA) is cut downstream of the connection point (on the left side of the drawing).

[0027] The heating temperature by the impulse heater is not particularly limited as long as it is equal to or higher than the melting point of the resin in the second resin sheet, but is, for example, 170°C or higher and 250°C or lower.

[0028] The pressure applied during welding is preferably adjusted so that the thickness of the connection portion is the thickness of one second resin sheet. This is because it is possible to further suppress steps (protruding burrs) at the connection portion. The pressure is, for example, 300 kN or more and 500 kN or less.

[0029] In the third step, it is preferable to cool the second resin sheet after welding, because this can prevent the second resin sheet from breaking. For example, it is preferable to cool the second resin sheet to a temperature of 80° C. or less.

[0030] Here, Fig. 2(d) is a schematic cross-sectional view illustrating an impulse heater used in the third step. As shown in Fig. 2(d), the impulse heater H preferably has a heating part Ha and a block part Hb. The shape of the heating part Ha preferably has a curved part (R-shape) C.

[0031] In the third step, similarly to the second step, it is preferable to arrange a second resin sheet on a first surface in the thickness direction of the current collector and on a second surface opposite to the first surface, thereby covering the region of the current collector including the long side (long side region).

[0032] 4. 4th step The fourth step is to place a separator on the cross-linked composite sheet. As described above, the electrode composite layer may be placed on both sides of the current collector, or on one side. In the former case, the separator is usually placed on one side of the electrode composite layer.

[0033] In the fourth step, the separator is preferably welded to the first and second resin sheets. The welding method is not particularly limited, but examples thereof include a method of heating and welding the separator with a laser. The type of laser is not particularly limited, but examples thereof include a gas laser such as a CO laser.

[0034] The material of the separator is not particularly limited as long as it is a porous film, and examples thereof include resins such as polyethylene (PE), etc. The thickness of the separator is, for example, 0.1 μm or more and 1000 μm or less.

[0035] 5. 5th step The fifth step is a step of cutting the crosslinked composite sheet into individual electrode composite layers. The cutting method is not particularly limited and may be a conventionally known method. This step yields an electrode, which will be described later.

[0036] 6. Electrode The electrode manufactured by the above-described process may be a negative electrode having a current collector, a negative electrode active material layer, and a separator in this order, or a positive electrode having a current collector, a positive electrode active material layer, and a separator in this order. The electrode may also be a bipolar electrode having a negative electrode active material layer, a current collector, and a positive electrode active material layer in this order. In a bipolar electrode, a separator is disposed on the negative electrode active material layer or the positive electrode active material layer. Furthermore, as shown in FIG. 1(f), the outer edge of the current collector 1 is preferably covered with the first resin sheet 20S and the second resin sheet 20L described above.

[0037] The electrodes in the present disclosure are generally used in batteries. The batteries are typically liquid batteries. The type of battery is not particularly limited, but examples include lithium-ion secondary batteries. Applications of the batteries include power sources for vehicles such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), electric vehicles (BEVs), gasoline-powered vehicles, and diesel-powered vehicles. In particular, the batteries are preferably used as driving power sources for hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), or electric vehicles (BEVs). The batteries may also be used as power sources for mobile objects other than vehicles (for example, railways, ships, and aircraft), and may also be used as power sources for electrical appliances such as information processing devices.

[0038] The present disclosure is not limited to the above-described embodiments. The above-described embodiments are merely examples, and any configuration that is substantially identical to the technical idea described in the claims of the present disclosure and that provides similar effects is included within the technical scope of the present disclosure. [Explanation of symbols]

[0039] 1...Current collector 2...Electrode composite material layer 10... Composite sheet 20S...First resin sheet 20L...Second resin sheet 20LA...Second resin sheet A 20LB...Second resin sheet B 30...Separator 100...electrode R...Roll H...Impulse heater

Claims

[Claim 1] a first step of preparing a plurality of composite sheets each having a current collector and an electrode composite layer disposed on at least one surface of the current collector, the composite sheets having long sides and short sides in a planar shape; A second step of cross-linking the short sides of the composite sheets adjacent to each other in the extending direction of the long sides using a first resin sheet; A third step of cross-linking the long sides of the composite sheets adjacent to each other in the extending direction of the long sides using a second resin sheet; a fourth step of disposing a separator on the electrode mixture layer of the crosslinked mixture sheet; a fifth step of cutting the crosslinked composite sheet into individual electrode composite layers, In the third step, the long sides are crosslinked using a second resin sheet A supplied from a first roll and a second resin sheet B supplied from a second roll after the second resin sheet A, and The second resin sheet A and the second resin sheet B are welded and connected to each other while being pressurized by an impulse heater.

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